This invention relates to an apparatus for collecting a blood sample, and more particularly to a syringe-like apparatus having a hollow interior capillary cartridge for receiving a blood sample in a manner to effectively contain the collected blood sample for subsequent analysis, for example pH and blood gas analysis. More specifically the invention pertains to a capillary cartridge having fluid inlet and fluid outlet means for receiving the blood sample, for expelling air or other gaseous fluid contaminants from its interior and for effectively containing the blood sample essentially free of contamination from gases and other materials.
In blood gas analysis, it is important that contaminants not be allowed to contact or mingle with the arterially collected blood sample. Typical contaminants which could introduce significant error in analysis include air, other gases or fluids, and possibly even solid materials. It is also important that the arterially collected blood sample be prevented from clotting. To this end it is typical to precondition the container into which the blood sample is received with an anticoagulant such as heparin solution. However, with such anticoagulant solutions, the dilutent of the solution may dilute the gases in the sample or cause contamination of the sample.
Therefore, it is desirable in taking arterial blood samples for analysis to isolate the blood sample from extraneous gaseous materials and from the dilutent of the anticoagulant solution while leaving the anticoagulant itself to prevent coagulation of the blood prior to analysis.
Accordingly, it is the general object of the invention to provide a new and improved apparatus to collect at least one arterial blood sample and to effectively isolate the blood sample in a capillary cartridge or tube after collection while preventing and avoiding contamination of the collected blood sample from gases and other foreign material.
Other objects of the invention are to provide a new and improved apparatus to collect at least one arterial blood sample in which the apparatus allows use of the blood sample during an analysis, significantly reduces the probability for error in the analysis results by eliminating or reducing the probability that contaminants may enter the blood sample, effectively avoids or prevents leakage of the blood sample after collection, and is easily and conveniently constructed and used.